Unit Testing - Is it bad form to have unit test calling other unit tests

Question

I have a unit test called TestMakeAValidCall(). It tests my phone app making a valid call.

I am about to write another test called TestShowCallMe

Answer 1

I think its a bad idea. You want your unit test to test one thing and one thing only. Instead of creating a call through your other test, mock out a call and pass it in as an argument.